Release v23.12.02 includes an update to the Apache2 server’s module and configuration to disable php8.1 and mpm_prefork and enable mpm_event and http2. Note: Submitty uses php8.1-fpm NOT php8.1.

1. If you have load balancers and firewalls in front of the Apache server for Submitty, please make sure they support HTTP/2 redirections.

2. Disable php8.1 and mpm_prefork:

   a2dismod php8.1 mpm_prefork
   

3. Enable mpm_event and http2:

   a2enmod mpm_event http2
   

4. If you are not already using TLS/SSL HTTPS encryption for Submitty, we strongly recommend enabling it. See System Administrator Installation Instructions.

5. Review your current performance tuning for php-fpm.

   /etc/php/8.1/fpm/pool.d/submitty.conf
   

   You will probably not need to change these settings.

6. With the switch from mpm_prefork to mpm_event, you will probably want to take any customization from this file:

   /etc/apache2/mods-available/mpm_prefork.conf
   

   And adapt it to this file:

   /etc/apache2/mods-available/mpm_event.conf
   

7. Final check for Apache2’s configuration;

   apachectl -t
   

8. Reload Apache2 to apply changes.

   sudo systemctl restart apache2.service
   sudo systemctl restart php8.1-fpm
   

9. Run the update script.

   sudo /usr/local/submitty/.setup/INSTALL_SUBMITTY.sh
   

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NOTE: If you need to downgrade from HTTP/2 back to HTTP/1.1 and re-enable mpm_prefork, please follow the steps below:

1. Disable http2 and mpm_event:

   a2dismod http2 mpm_event
   

2. Enable mpm_prefork:

   a2enmod mpm_prefork
   

3. Alternatively, if the PHP does not use a fpm server, consider enabling php8.1 by a2enmod php8.1.